These valves are manufactured from a Nickel base super alloy material (Inconel 751 or Nimonic 80A) this material is chosen because it is designed to withstand very high temperatures. These valves feature a one-piece forging, hardened tip, and “superfinish” stem. a must for turbos. Exhaust valve 29.9mm, For 1.8T 20v and 2.7T, 2.8L & 3.0L 30v V6 heads. Uses std triple groove keepers. Higher...These valves are manufactured from a Nickel base super alloy material (Inconel 7...